The Age-Related Eye Disease Studies (AREDS and AREDS2) established that dietary supplements could slow the progression of age-related macular degeneration (AMD), the most common cause of blindness in older Americans.
Scientists from the National Eye Institute found that the AREDS2 formula, which substituted antioxidants lutein and zeaxanthin for beta-carotene, not only reduces the risk of lung cancer due to beta-carotene but is also more effective at reducing the risk of AMD progression, compared to the original formula.
The research is published in JAMA Ophthalmology and was conducted by Emily Chew et al.
AMD is a degenerative disease of the retina, the light-sensitive tissue at the back of the eye. Progressive death of retinal cells in the macula, the part of the retina that provides clear central vision, eventually leads to blindness.
Treatment can slow or reverse vision loss; however, no cure for AMD exists.
The original AREDS study, launched in 1996, showed that a dietary supplement formulation (500 mg vitamin C, 400 international units vitamin E, 2 mg copper, 80 mg zinc, and 15 mg beta-carotene) could significantly slow the progression of AMD from moderate to late disease.
In AREDS2, begun in 2006, the team compared the beta-carotene formulation to one with 10 mg lutein and 2 mg zeaxanthin instead. Like beta-carotene, lutein and zeaxanthin are antioxidants with activity in the retina.
The beta-carotene-containing formation was only given to participants who had never smoked or who had quit smoking.
At the end of the five-year AREDS2 study period, the researchers concluded that lutein and zeaxanthin did not increase the risk of lung cancer and that the new formation could reduce the risk of AMD progression by about 26%.
After the completion of the five-year study period, the participants were all offered the final AREDS2 formation that included lutein and zeaxanthin instead of beta-carotene.
In this new study, the researchers followed up with 3,883 of the original 4,203 AREDS2 participants an additional five years from the end of the AREDS2 study in 2011, collecting information on whether their AMD had progressed to late disease, and whether they had been diagnosed with lung cancer.
Even though all the participants had switched to the formula containing lutein and zeaxanthin after the end of the study period, the follow-up study continued to show that beta-carotene increased the risk of lung cancer for people who had ever smoked by nearly double.
There was no increased risk for lung cancer in those receiving lutein/zeaxanthin.
In addition, after 10 years, the group originally assigned to receive lutein/zeaxanthin had an additional 20% reduced risk of progression to late AMD compared to those originally assigned to receive beta-carotene.
These results confirmed that switching the formula from beta-carotene to lutein and zeaxanthin was the right choice.
If you care about eye health, please read studies about a new drug for diabetic eye disease, and this common vitamin may protect against blinding eye disease.
For more information about supplements, please see recent studies about vitamins that could protect against respiratory infections, and results showing this vitamin is particularly important for your cancer prevention.
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